Ink jet printing is a non-impact means of producing a pattern of ink droplets which can be used to record digital information. To make a hard copy, the droplets are deposited onto a transparent, translucent, or opaque support such as film, vellum or paper. Ink jet printers have been used for many years to make monochrome hard copy from computers. A rapidly-growing use of ink jet printers is to generate subtractive color images using a three- or four-color process. The resultant hard copy can be viewed by transmitted light using an overhead projector (transparent film); by transmitted light using a diffuse illuminator (translucent film); or by reflected light (opaque support).
In subtractive continuous tone silver halide color photography, color images are produced by the superposition of three primary continuous-tone color-intensity-graduated recording layers. In non-continuous tone ink jet color printing, use is made of microscopic superposed color-separated dots (so-called halftone images) to create an impression to the viewer of an intensity graduated image. The proper hue, size, and degree of coalescence and mixing of the primary color dots--cyan, magenta, yellow and black--are necessary for the faithful reproduction of color on the recording medium. Accurate ink jet color image recording thus requires a high degree of cooperation between the ink jet color separation pulses, the ink dyestuffs, and the ink acceptor material.
An ink acceptor material should be capable of accepting the droplets readily and allowing them to coalesce, yet should achieve color isolation and separation with high chroma and pure hue without image edge distortions due to poor registration, bleeding, leathering, or other image quality defects. Acceptor materials for colored inks currently available, however, suffer from rapid fading of one or more of the dyestuffs upon exposure to light, heat, or high humidity storage conditions. Furthermore, inked acceptor materials are not water-resistant, and images thereon can be degraded easily by handling or by contact with moist objects. Fingers and other moist objects contacting the images often become stained with the dyestuffs. Also, because the usual aqueous ink jet inks have relatively low volatility, imaged acceptor materials are typically still wet with the aqueous ink vehicle when emerging from an ink jet printer. Images are then most vulnerable and can be altered by smudging or blocking (print stacking). Thus, there is a need for an ink acceptor material capable of rendering ink jet images which dry rapidly, are resistant to adverse effects of fingerprints, handling, high humidity storage, water spills, and the like, and which show a high degree of stability to light. Such attributes will be highly useful in extending ink jet imaging to, for example, mail addressing, airline tickets, outdoor advertising displays, T-shirt printing, and posters-on-demand type applications.